[填空题]
Estimate the resistance of thea uw4b:f( w a*2 dmm,0g5 wa(5drdumlp3/ffjlxnbng.v bs9yi* gc-74 uwq, x4 $120-V_{rms}$ circuits in your house as seen by the power company, when
(a) everything electrical is unplugged,
(b) there is a lone 75-W lightbulb burning. $\Omega$
